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Road induced edge effects on a forest bird community in tropical Asia

Avian Research 2018年第2期9卷 123-135页

作者： Daphawan Khamcha Richard T.Corlett Larkin A.Powell Tommaso Savini Antony j.Lynam george A.Gale Conservation Ecology Program School of Bioresources and Technology King Mongkut’s University of Technology Thonburi Center for Integrative Conservation Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences School of Natural Resources University of Nebraska-Lincoln Wildlife Conservation Society Global Conservation Program

Background: Edge effects cause changes in bird community richness, abundance, and/or distribution within a landscape, but the avian guilds most influenced can vary among regions. Although Southeast Asia has the highest rates of deforestation and projected species loss, and is currently undergoing an explosive growth in road infrastructure, there have been few studies of the effects of forest edges on avian communities in this ***: We examined avian community structure in a dry evergreen forest in northeastern Thailand adjacent to a five-lane highway. We evaluated the richness and abundance of birds in 11 guilds at 24 survey points on three parallel transects perpendicular to the edge. At each point, 10-min surveys were conducted during February-August 2014 and March-August 2015. Vegetation measurements were conducted at 16 of the bird survey points and ambient noise was measured at all 24 survey ***: We found a strongly negative response to the forest edge for bark-gleaning, sallying, terrestrial, and understory insectivores and a weakly negative response for arboreal frugivore-insectivores, foliage gleaning insectivores, and raptors. Densities of trees and the percentage canopy cover were higher in the interior, and the ambient noise was lower. In contrast, arboreal nectarivore-insectivores responded positively to the forest edge, where there was a higher vegetation cover in the ground layer, a lower tree density, and a higher level of ambient ***: Planners should avoid road development in forests of high conservation value to reduce impacts on biodiversity. Where avoidance is impossible, a number of potential mitigation methods are available, but more detailed assessments of these are needed before they are applied in this region.

关键词： Road edge Avian guilds Dry evergreen forest Thailand

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Acute upper gastrointestinal bleeding in octοgenarians:Clinical outcome and factors related to mortality

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World journal of Gastroenterology 2008年第25期14卷 4047-4053页

作者： george j Theocharis Vassiliki Arvaniti Stelios F Assimakopoulos Konstantinos C Thomopoulos Vassilis Xourgias Irini Mylonakou Vassiliki N Nikolopoulou Division of Gastroenterology Department of Internal Medicine University Hospital of Patras Department of Gastroenterology "Tzaneio" General Hospital Department of Internal MedicineUniversity Hospital of Patras

AIM: To evaluate the aetiology, clinical outcome and factors related to mortality of acute upper gastrointestinal bleeding (AUGIB) in octogenarians. METHODS: We reviewed the records of all patients over 65 years old who were hospitalised with AUGIB in two hospitals from january 2006 to December of 2006. Patients were divided into two groups: Group A (65-80 years old) and Group B (> 80 years old). RESULTS: Four hundred and sixteen patients over 65 years of age were hospitalized because of AUGIB. Group A included 269 patients and Group B 147 patients. Co-morbidity was more common in octogenarians (P = 0.04). The main cause of bleeding was peptic ulcer in both groups. Rebleeding and emergency surgery were uncommon in octogenarians and not different from those in younger patients. In-hospital complications were more common in octogenarians (P = 0.05) and more patients died in the group of octogenarians compared to the younger age group (P = 0.02). Inability to perform endoscopic examination (P = 0.002), presence of high risk for rebleeding stigmata (P = 0.004), urea on admission (P = 0.036), rebleeding (P = 0.004) and presenceof severe co-morbidity (P < 0.0001) were related to mortality. In multivariate analysis, only the presence of severe co-morbidity was independently related to mortality (P = 0.032). CONCLUSION: While rebleeding and emergency surgery rates are relatively low in octogenarians with AUGIB, the presence of severe co-morbidity is the main factor of adverse outcome.

关键词： Acute upper gastrointestinal bleeding Octogenarians Elderly Co-morbidity Mortality

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Virtual endoscopy of the urinary tract

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Asian journal of Andrology 2006年第1期8卷 31-38页

作者： george C.Kagadis Dimitrios Siablis Evangelos N.Liatsikos Theodore Petsas george C. Nikiforidis Department of Medical Physics Department of Radiology Department of Urology School of MedicineUniversity of PatrasGR 26500 RionGreece Department of Radiology Department of Medical Physics

Technological breakthroughs have advanced the temporal and spatial resolutions of diagnostic imaging, and 3 dimensional （3-D） reconstruction techniques have been introduced into everyday clinical practice. Virtual endoscopy （VE） is a non-invasive technique that amplifies the perception of cross-sectional images in the 3-D space, providing precise spatial relationships of pathological regions and their surrounding structures. A variety of computer algorithms can be used to generate 3-D images, taking advantage of the information inherent in either spiral computed tomography or magnetic resonance imaging （MRI）. VE images enable endoluminal navigation through hollow organs, thus simulating conventional endoscopy. Several clinical studies have validated the diagnostic utility of virtual cystoscopy, which has high sensitivity and specificity rates in the detection of bladder tumor. Published experience in the virtual exploration of the renal pelvis, ureter and urethra is encouraging but still scarce. VE is a safe, non-invasive method that could be applied in the long-term follow-up of patients with ureteropelvic junction obstruction, urinary bladder tumors and ureteral and/or urethral strictures. Its principal limitations are the inability to provide biopsy tissue specimens for histopathologic examination and the associated ionizing radiation hazards （unless MR/is used）. However, in the case of endoluminal stenosis or obstruction, VE permits virtual endoluminal navigation both cephalad and caudal to the stenotic segment. To conclude, VE provides a less invasive method of evaluating the urinary tract, especially for clinicians who are less familiar with cross-sectional imaging than radiologists. （Asian j Androl 2006 jan; 8： 31-38）

关键词： computed tomography three-dimensional imaging virtual endoscopy urethral stricture

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Efficient and Accurate Numerical Methods Using the Accelerated Spectral Deferred Correction for Solving Fractional Differential Equations

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Numerical Mathematics(Theory,Methods and Applications) 2022年第4期15卷 876-902页

作者： Xuejuan Chen Zhiping Mao george Em Karniadakis School of Science Jimei UniversityXiamen 361021China School of Mathematical Sciences Fujian Provincial Key Laboratory of Mathematical Modeling and High-Performance Scientific ComputingXiamen UniversityXiamenChina Division of Applied Mathematics Brown UniversityProvidenceRI 02912USA

We develop an efficient and accurate spectral deferred correction(SDC)method for fractional differential equations(FDEs)by extending the algorithm in[14]for classical ordinary differential equations(ODEs).Specifically,we discretize the resulted Picard integral equation by the SDC method and accelerate the convergence of the SDC iteration by using the generalized minimal residual algorithm(GMRES).We first derive the correction matrix of the SDC method for FDEs and analyze the convergence region of the SDC *** then present several numerical examples for stiff and non-stiff FDEs including fractional linear and nonlinear ODEs as well as fractional phase field models,demonstrating that the accelerated SDC method is much more efficient than the original SDC method,especially for stiff ***,we resolve the issue of low accuracy arising from the singularity of the solutions by using a geometric mesh,leading to highly accurate solutions compared to uniform mesh solutions at almost the same computational ***,for long-time integration of FDEs,using the geometric mesh leads to great computational savings as the total number of degrees of freedom required is relatively small.

关键词： Stiff problem generalized minimal residual geometric mesh refinement long time evolution fractional phase field models

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An Adaptive Approach for Hazard Regression Modeling

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Open journal of Statistics 2023年第3期13卷 300-315页

作者： george j. Knafl School of Nursing University of North Carolina at Chapel Hill Chapel Hill USA

Regression models for survival time data involve estimation of the hazard rate as a function of predictor variables and associated slope parameters. An adaptive approach is formulated for such hazard regression modeling. The hazard rate is modeled using fractional polynomials, that is, linear combinations of products of power transforms of time together with other available predictors. These fractional polynomial models are restricted to generating positive-valued hazard rates and decreasing survival times. Exponentially distributed survival times are a special case. Parameters are estimated using maximum likelihood estimation allowing for right censored survival times. Models are evaluated and compared using likelihood cross-validation (LCV) scores. LCV scores and tolerance parameters are used to control an adaptive search through alternative fractional polynomial hazard rate models to identify effective models for the underlying survival time data. These methods are demonstrated using two different survival time data sets including survival times for lung cancer patients and for multiple myeloma patients. For the lung cancer data, the hazard rate depends distinctly on time. However, controlling for cell type provides a distinct improvement while the hazard rate depends only on cell type and no longer on time. Furthermore, Cox regression is unable to identify a cell type effect. For the multiple myeloma data, the hazard rate also depends distinctly on time. Moreover, consideration of hemoglobin at diagnosis provides a distinct improvement, the hazard rate still depends distinctly on time, and hemoglobin distinctly moderates the effect of time on the hazard rate. These results indicate that adaptive hazard rate modeling can provide unique insights into survival time data.

关键词： Adaptive Regression Fractional Polynomials Hazard Rate Likelihood Cross-Validation Survival Times

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Adaptive Conditional Hazard Regression Modeling of Multiple Event Times

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Open journal of Endocrine and Metabolic Diseases 2023年第4期13卷 492-513页

作者： george j. Knafl School of Nursing University of North Carolina at Chapel Hill Chapel Hill NC USA

Recurrent event time data and more general multiple event time data are commonly analyzed using extensions of Cox regression, or proportional hazards regression, as used with single event time data. These methods treat covariates, either time-invariant or time-varying, as having multiplicative effects while general dependence on time is left un-estimated. An adaptive approach is formulated for analyzing multiple event time data. Conditional hazard rates are modeled in terms of dependence on both time and covariates using fractional polynomials restricted so that the conditional hazard rates are positive-valued and so that excess time probability functions (generalizing survival functions for single event times) are decreasing. Maximum likelihood is used to estimate parameters adjusting for right censored event times. Likelihood cross-validation (LCV) scores are used to compare models. Adaptive searches through alternate conditional hazard rate models are controlled by LCV scores combined with tolerance parameters. These searches identify effective models for the underlying multiple event time data. Conditional hazard regression is demonstrated using data on times between tumor recurrence for bladder cancer patients. Analyses of theory-based models for these data using extensions of Cox regression provide conflicting results on effects to treatment group and the initial number of tumors. On the other hand, fractional polynomial analyses of these theory-based models provide consistent results identifying significant effects to treatment group and initial number of tumors using both model-based and robust empirical tests. Adaptive analyses further identify distinct moderation by group of the effect of tumor order and an additive effect to group after controlling for nonlinear effects to initial number of tumors and tumor order. Results of example analyses indicate that adaptive conditional hazard rate modeling can generate useful insights into multiple event time data.

关键词： Adaptive Regression Fractional Polynomials Hazard Rate Multiple Event Times Recurrent Events

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Adaptive Regression for Nonlinear Interrupted Time Series Analyses with Application to Birth Defects in Children of Vietnam War Veterans

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Open journal of Statistics 2022年第6期12卷 789-809页

作者： george j. Knafl School of Nursing University of North Carolina at Chapel Hill Chapel Hill NC USA

The purpose of this article is to provide an overview of adaptive regression modeling and demonstrate its use in conducting nonlinear analyses of interrupted time series (ITS) data. Adaptive regression modeling is based on heuristic search over alternative models for data controlled by likelihood-cross validation (LCV) scores with larger scores indicating better models. Extended linear mixed models are used for correlated data like ITS data. Power transforms of predictor variables are used to account for nonlinearity. The use of adaptive regression modeling for assessing ITS effects is demonstrated using data on annual proportions of major birth defects in children fathered by male Air Force veterans of the Vietnam War over a 59-year period. The interruption for this ITS is conception after versus before the start of a participant’s first tour in the Vietnam War. Whether the ITS effect is related to dioxin exposure is also addressed. Dioxin is a highly toxic contaminant of the herbicide Agent Orange used in the Vietnam War. The core findings of the reported analyses are that a substantial adverse ITS interruption effect is identified and that this adverse effect can reasonably be attributed to participants having a high dioxin exposure level. Moreover, these results indicate that adaptive regression modeling can identify nonlinear ITS effects in general situations that can lead to consequential insights into nonlinear relationships over time, possibly varying with other available predictors.

关键词： Adaptive Regression Air Force Health Study Birth Defects Dioxin Inter-rupted Time Series

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Use of direct-acting antiviral agents in hepatitis C virusinfected liver transplant candidates

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World journal of Gastroenterology 2018年第3期24卷 315-322页

作者： Chiranjeevi Gadiparthi george Cholankeril Brandon j Perumpail Eric R Yoo Sanjaya K Satapathy Satheesh Nair Aijaz Ahmed Division of Gastroenterology and Hepatology University of Tennessee Health Sciences CenterMemphisTN 38104United States Division of Gastroenterology and Hepatology Stanford University School of MedicineStanfordCA 94304United States Drexel University College of Medicine PhiladelphiaPA 19129United States Department of Medicine Santa Clara Valley Medical CenterSan JoseCA 95128United States

Since the advent of direct acting antiviral(DAA) agents, chronic hepatitis C virus(HCV) treatment has evolved at a rapid pace. In contrast to prior regimen involving ribavirin and pegylated interferon, these newer agents are highly effective, well-tolerated, have shorter course of therapy and safer essentially in all HCV patients including those with advanced liver disease and following liver transplantation. Clinicians caring for HCV-infected patients on the liver transplant(LT) waitlist are often faced with a dilemma whether to treat HCV infection before or after liver transplantation. Sustained virological response(SVR) rates following HCV treatment may improve hepatic function sufficiently enough to negate the need for LT in certain patients. On the other hand, the decrease in MELD without improvement in quality of life in certain patients may lead to delay or dropout from potentially curative LT surgery list. In this context, our review focuses on the approach to and optimal timing of DAA-based treatment of HCV infection in LT candidates in the peri-transplant period.

关键词： Hepatitis C virus Direct-acting antiviral therapy Liver transplantation Purgatory Model for End-stage liver disease Sustained virological response

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Force-based and displacement-based reliability assessment approaches for highway bridges under multiple hazard actions

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journal of Traffic and Transportation Engineering(English Edition) 2015年第4期2卷 223-232页

作者： Chao Huang jerry j.Shen Mi Zhou george C.Lee Department of Civil Structural and Environmental Engineering University at Buffalo Genex Systems/TFHRC 6300 Georgetown Pike Mc Lean 22101 USA National Engineering and Research Center for Highways in Mountain Area Key Laboratory for Old Bridge Detection and Reinforcement Technology of Ministry of Transportation Chang'an University

The strength limit state of American Association of State Highway and Transportation Officials （AASHTO） Load and Resistance Factor Design （LRFD） Bridge Design Spec/fications is developed based on the failure probabilities of the combination of non-extreme loads. The proposed design limit state equation （DLSE） has been fully calibrated for dead load and live load by using the reliability-based approach. On the other hand, most of DLSEs in other limit states, including the extreme events i and li, have not been developed and calibrated though taking certain probability-based concepts into account. This paper presents an assessment procedure of highway bridge reliabilities under the limit state of extreme event i, i. e,, the combination of dead load, live load and earthquake load. A force-based approach and a displacement-based approach are proposed and implemented on a set of nine simplL^ed bridge models. Results show that the displacement-based approach comes up with more convergent and accurate reliabilities for selected models, which can be applied to other hazards.

关键词： BridgeReliability assessmentMultiple hazardsLoadResistance

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Novel immunotherapy approaches for metastatic urothelial and renal cell carcinoma

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Asian journal of Urology 2016年第4期3卷 268-277页

作者： Zhiying Shao Andrew Z.Wang Daniel j.george Tian Zhang Department of Medical Oncology The Affiliated Hospital of Xuzhou Medical UniversityJiangsu Center for the Collaboration and Innovation of Cancer BiotherapyCancer InstituteXuzhou Medical UniversityXuzhouJiangsuChina Department of Radiation Oncology Lineberger Comprehensive Cancer CenterUniversity of North Carolina-Chapel HillChapel HillNCUSA Division of Medical Oncology Department of MedicineDivision of UrologyDepartment of SurgeryDuke Cancer InstituteDuke University Medical CenterDurhamNCUSA Division of Medical Oncology Department of MedicineDuke Cancer InstituteDuke University Medical CenterDurhamNCUSA

The treatment of metastatic renal cell carcinoma(RCC)and urothelial carcinoma(UC)remains a major *** research has implicated the immune system in tumor surveillance of both malignancies,leading to the application of immunotherapy agents for both *** them,the most promising agents are the checkpoint blockade drugs,such as antibodies targeting the cytotoxic T-lymphocyte-associated antigen 4(CTLA-4),programmed death receptor 1(PD-1),and PD-1 ligand(PD-L1).In normal physiology,these immune checkpoints act as inhibitory signals to fine-tune the duration and strength of immune reactions,which is pivotal for maintaining ***,tumor cells also utilize immune checkpoint pathways to evade anti-tumor immune response,leading to disease progression and ***,there has been intense preclinical and clinical effort focused on the application of checkpoint inhibitors in metastatic RCC and *** date,nivolumab(anti-PD-1)and atezolizumab(anti-PD-L1)have been approved for the treatment of metastatic RCC and UC,*** these successes,challenges remain in how to further improve response rates to immunotherapy and how to select patients that will benefit from this *** this report,we review existing data and research on immunotherapy in metastatic RCC and UC.

关键词： Immune checkpoint inhibitors Nivolumab Atezolizumab Pembrolizumab Renal cell carcinoma Urothelial carcinoma

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